Process of treating molten metal



un 18', 1935] E. P. FLEMING ET AL 2,005,540

PROCESS OF TREATING MOLTEN METAL Fiied Sept. 28, 1933 ATTORNEYS atented June 18, 1935 UNITED STATES PROCESS OF TREATING MOLTEN METAL Edward P. Fleming, Salt Lake City, Utah, and

' Sidney L. Palmer,

San Francisco, Calif., as-

signors to- American Smelting'and Refining Company, New-York, N. Y., a corporation of New Jersey Application September gs, 1933, Serial No. 691.282

6 Claims. (Cl. 75-1?) This invention relates to an improved process of introducing reagents into molten metal and agitating the metal in a novel manner to thoroughly incorporate the reagents therein thereby effecting the desired reactions.

In accordance with the invention, a molten bath is established comprising the metal to be treated and the desired reagent is placed beneath the surface of the bath in a wooden container in a manner calculated to release the reagent as desired and to agitate and set up a circulation Within the body of the bath, by which a thorough diffusion of the reagent throughout the metal is effected without recourse to any additional means of a manual, mechanical or other nature.

Although the novel features which are believed to, be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may be, carried out, may be better understood by referring to the following description taken in connection with the accompanying drawing forming a part thereof, in which Fig. 1 is a cross section of an ordinary refining kettle illustrating one manner in which the reagent may be incorporated in the molten metal;

Fig. 2 is a perspective view of one type of wooden container suitable for use in accordance with the invention;

Fig.3 is a side view of the container shown in Fig; 2;

Fig. 4 is a bottom plan view of the container shown in Figs. 2 and 3; a

Fig. 5 is a side view of a modifiedform of container with a portion broken away; and

Fig. 6 is a cross section of the container shown in Fig. 5.

Like reference characters the several figures of the drawing.

In the following description and in the claims, various details will be identified by specific names for convenience, but they are intended 'to be-as generic in their application as the art will permit.

Referring now to Fig. 1, l represents an ordinary cast ironrefining kettle, supported on beams 2 and filled to the level 3 with molten metal 0. Wooden box 5 containing the reagent is held in position near the bottom of .the bath by iron rod 6 secured to beam 1.

In Fi 2, 3, and 4 are shown a wooden box 5 having sides 8, ends 9 and top 10. A block of Wood M is secured to the top W of box 5 by a suitable strap of metal l2. Iron rod 6 extends into block Ill and provides means for stabilizing the position of box 5 when in use.

In the modified container, shown in Figs. 5 and denote like parts in.

6, a block of wood i3 is shown with holes l4 adapted to contain the desired reagent.

In practising the invention, the container holding the reagent may be submerged in the bath of molten metal and held in the desired position, as illustrated in Fig. 1. Upon introducing the wooden box containing the reagent into the molten metal violent agitation of the bath is effected as a result of the reaction between the wood and the metal. This reaction results in a rapid evolution of gas in the vicinity of the center of the bath and the gases ascending vertically from the lower central portion of the bath carry the metal upwardly to the surface thereof, from whence it spreads out horizontally across the surface and downwardly along the sides of the kettle, thus effecting a continuous circulation of the metal within the kettle. .By reason of this circulation, the metal iscaused to continuously flow in contact with the reagent, thus obtaining the desired reactions.

To further illustrate the invention, the following specific examples of the improved process as applied to the treatment of white metal alloys with sulfur are given:

Errample 1 Approximately 5 tons of an alloy comprising 86.58% lead, 5.55% tin, 7.8% antimony and 0.072% copper were treated in accordance with the method heretofore described with '24 lbs. of sulfur. The time required for treatment was 40 minutes and the temperature of the bath at that time was 625 F. An analysis of the sample of the bath revealed a copper content of 0.015%.

Example 3 In this instance, antimonial lead analyzing 10.2% antimony, 0.90% tin, 0.60% copper and the balance lead was treated in accordance with the invention by submerging a small wooden box containing sulfur in the lower central portion of the bath. When the reaction was complete, the metal was analyzed and found to contain only 0.004% copper. I

It will be appreciated that, while the invention has been described for purposes of illustration as applied to the treatment of lead, white metal alloys or the like with sulfur, it is equally applicable to the treatment of other metals with different reagents.

Various advantages of the invention will be readily apparent to those skilled in the art. For example, it makes for economy in the amount of reagent or reagents necessary to accomplish the desired reaction as the reagent is introduced below the surface of the bath and cannot escape the-efrom without first passing upwardly through the whole mass of molten metal. Again, an economy in labor is effected because after placing the reagent in position in the molten metal. no further attention need be directed to the operation until same is completed. Also, power requirements for mechanically or otherwise agitating the bath are eliminated.

As heretofore stated, the wood container serves as a means for agitating the metal by effecting the evolution of gases thereby causing the metal to continuously circulate within the kettle. In addition, the wood exerts a purifying effect by removing oxides which may be present in the metal. Again, the wood being a poor conductor of heat effectively insulates the sulfur or other reagent used from the molten metal except at the exposed surface, thus preventing too rapid heating of the reagent and volatilization losses thereof which would otherwise result.

While certain novel features of the invention have been disclosed and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. The method of incorporating a reagent in a bath of molten metal which comprises confining the reagent in a \voodencontainer in such manner that the reagent is partially exposed and submerging said container in the bath of' molten metal in such manner that the exposed surface of the reagent faces downwardly in the metal bath.

2. The process of treating white metal alloys with sulfur which comprises casting molten sulfur in a wooden box open on one side thereby exposing the sulfur, allowing the sulfur to solidify and thereafter submerging said box in a molten bath of a white metal alloy in such position that the exposed surface of sulfur faces downwardly in said bath.

3. The method of incorporating sulfur in white metal alloys to effect the removal of copper as a dross which comprises casting molten sulfur in a wooden container and submerging the container in a molten bath of white metal thereby effecting agitation of the bath and diffusing sulfur through the body thereof by the evolution of gas resulting from the reaction between the wood and molten metal.

l. The improved method of decopperizing metal by the use of sulfur which comprises submerging a wooden container of sulfur having a portion ,of the sulfur exposed in a molten bath of the metal. I

5. The improved method of treating white metal alloys with sulfur which comprises submerging a wooden container of sulfur having a portion of the sulfur exposed in a molten bath of a white metal alloy.

An improved process for incorporating a normally solid reagent in a bath of molten metal which consists in charging the reagent in a wooden container in such a manner that a surface of the reagent is exposed and placing said charged container in the lower portion of said molten bath whereby the reaction between the wood and metal effects circulation of the latter and causes same to intimately contact the exposed surface of the reagent.

EDWARD P. FLEMING. SIDNEY L. PALMER. 

